The Effects of Interferon-gamma on Sepsis-induced Immunoparalysis

• The primary endpoint is the tumor necrosis factor (TNF)-α secretion by ex vivo lipopolysaccharide (LPS)-stimulated leukocytes as a marker of immunosufficiency/antimicrobial response. [ Time Frame: at admission and at days 0, 2, 7, 14 and 28 ] [ Designated as safety issue: No ]
  

• Outcome of bacterial infection (occurrence of secondary and/or opportunistic infections, duration of antibacterial treatment, microbiological evaluation) [ Time Frame: At days 0, 2, 7, 14 and 28 ] [ Designated as safety issue: No ]
  
• Hemodynamic stability (noradrenalin infusion rate, amount of infused fluids per day, amount of urine produced per day, daily fluid balance) [ Time Frame: At days 0, 2, 7, 14 and 28 ] [ Designated as safety issue: No ]
  
• Mortality (including time to death) at week 2 and week 6 after end of treatment (all causes) [ Time Frame: At days 14 and 28 ] [ Designated as safety issue: Yes ]
  
• Length of stay at ICU and duration of hospitalization [ Time Frame: At days 28 and 56 ] [ Designated as safety issue: No ]
  
• Organ function [ Time Frame: at days 0, 14, and 28 ] [ Designated as safety issue: Yes ]
  • Cardiovascular function: lactate level, vasopressor usage, and cardiovascular Sequential Organ Failure Assessment (SOFA) score
  • Respiratory function: oxygenation index, Pulmonary Arterial Oxygen Tension (PaO2) / fraction of inspired oxygen (FiO2) (P/F) ratio, and respiratory SOFA score
  • Renal function: creatinine level, urine output, renal replacement therapy usage, and renal SOFA score
  • Hematologic function: hematologic SOFA score
  • Hepatic function: Hepatic SOFA score
  
  
• Production of other cytokines by leukocytes ex vivo stimulated with various stimuli (including LPS, peptidoglycan, candida) [ Time Frame: At admission, at days 0, 2, 7, 14, and 28 ] [ Designated as safety issue: No ]
  
• Markers of "immune status" (including human leukocyte antigen expression on monocytes (mHLA)-DR and programmed death (PD)-1 expression, interleukin (IL)-6 plasma concentration) [ Time Frame: At admission and at days 0, 2, 7, 14, and 28 ] [ Designated as safety issue: No ]
  
• the correlation between the level of immunoparalysis (indicated by the commonly used marker mHLA-DR and new markers of "immune status" found), and effectiveness of IFN-γ (indicated by TNF-α secretion by ex vivo LPS-stimulated PBMC's). [ Time Frame: At days 0, 14, and 28 ] [ Designated as safety issue: No ]
  
• Transcriptional activity of leukocytes, including microarrays with a focus on inflammatory pathways [ Time Frame: At admission and at days 0, 2, 7, 14, and 28 ] [ Designated as safety issue: No ]
  
• Changes in phenotype or gene expression caused by mechanisms other than changes in the underlying DNA sequence (epigenetic modifications) [ Time Frame: At admission and at days 0, 7, and 28 ] [ Designated as safety issue: No ]
  
• reversibility of monocytes tolerance [ Time Frame: Day 0 ] [ Designated as safety issue: No ]
  the reversibility of monocytes tolerance by the mean of innate immune training (cytokines production such as TNF and Interleukin (IL)-6 will be assessed).
  
  

Sepsis is the leading cause of death in the ICU with an estimated 6 million victims per year worldwide. Although septic shock is traditionally viewed as an excessive systemic inflammatory reaction to invasive microbial pathogens, pharmacological suppression of the innate immune response in sepsis has proved to be unsuccessful. An important reason for this might be that the vast majority of septic patients survive the initial pro-inflammatory hit, but die in the subsequent immunosuppressed state due to secondary/opportunistic infections. This so-called 'immunoparalysis' is increasingly recognized as the overriding immune dysfunction in septic patients. Reversal of sepsis-induced immunoparalysis is therefore a promising adjunctive treatment for patients presenting with septic shock.

It was demonstrated that interferon-gamma (IFN)-gamma can reverse immunoparalysis in vitro and in vivo in animals and in healthy volunteers. Moreover, in a case-series of septic patients interferon-gamma treatment leaded to reversal of immunoparalysis, reduction in mechanical ventilation time and length of stay with no relevant side-effects.

The primary aim of this study is to assess the effects of adjunctive therapy with IFN-gamma on immune function in patients with septic shock in a placebo-controlled manner. Moreover, the investigators want to evaluate new markers that could be used to identify patients with immunoparalysis, and to monitor the patient's immunological response to IFN-γ. In addition, mechanistic studies will be performed to further elucidate mechanisms (such as epigenetic modifications) behind immunoparalysis and the effects of IFN-γ on these mechanisms.